Effect of Using Different Blends of Non-Saccharomyces Yeast Isolated from Italia and Negra Criolla Grapes on the Aromatic Diversity and Sensory Profile of Piscos

Abstract

The objective of this study was to investigate the impact of co-fermentation of Italia and Negra Criolla grape musts using non-Saccharomyces yeast strains (NSYSs) isolated from both grape varieties, on the major volatile compounds and sensory characteristics of Piscos (distilled spirits). Native NSYSs previously isolated from Italia (Pichia terricola, Metschnikowia pulcherrima, and Naganishia vaughanmartiniae) and Negra Criolla (Vishniacozyma carnescens, Vishniacozyma heimaeyensis, and Aureobasidium pullulans) grapes’ skins were inoculated at the beginning of grape must fermentation. A centroid simplex design was applied in order to obtain 10 representative yeast blends for use as mono- (n = 3), bi- (n = 3), and ternary (n = 4) inoculations. Additionally, a control sample without inoculum was also set up. For each yeast blend, the volatile composition and sensory characteristics of Piscos were evaluated. Results showed that mono-inoculation using specific NSYSs, such as P. terricola, M. pulcherrima, and N. vaughanmartiniae, led to a notable predominance of some terpenes such as α-terpineol, citronerol, and geraniol in Pisco from Italia grapes compared to the control Pisco. Conversely, in Pisco from Negra Criolla grapes, where V. carnescens, V. heimaeyensis, and A. pullulans were used in a similar mono-inoculation process, a higher presence of phenylethyl alcohol and 2-phenylethyl acetate compared to the control was observed. The sensory analysis revealed that citrus, floral, alcohol, and syrup descriptors had a higher intensity in mono-inoculated Pisco Italia, whereas spice, herbaceous, and cooked vegetable descriptors had the highest intensity in Negra Criolla Piscos produced with ternary NSYS inoculum inoculations. This study demonstrates that the use of native non-Saccharomyces yeast strains in the co-fermentation of grape musts can significantly influence the volatile profile and sensory characteristics of Pisco. These findings will allow us to establish new inoculation strategies to impact the overall sensory and aromatic profile of the Piscos produced with different grape varieties.